Synthesis of spiro cyclopropane-oxyindole compounds by organic catalytic reaction

In this paper, four thiourea catalysts containing chiral carbon and C₂ chiral axis were designed and synthesized successfully, and they were used for the asymmetric synthesis of spiral cyclopropane-indole oxide compounds. The experimental results showed that the synthesis of spiro cyclopropane-oxyindole obtained better yield (89%) and higher enantioselectivity (87%) at room temperature 25 ℃ with 10 mol% 3a as catalyst and CHCl₃ as solvent. The reaction has the advantages of friendly environment, mild reaction condition and cheap catalyst. This method provides an important way for the synthesis of snail cyclopropane-oxyindole skeleton with biological pharmacological activity.